On Foxes 說狐

When foxes reach fifty years of age, they can transform into adult women. At a hundred years they can be beautiful girls, and perform sorcery. Some become husbands and enjoy carnal relations with women. They have awareness of matters extending up to a thousand li away. They are skilled at wielding noxious influence and charms, and can perplex and mislead people, stealing away their wisdom. At a thousand years they can receive the direct blessings of heaven, as a divine fox.

From Xuanzhongji.

Li Fang 李昉, et al., Taiping guangji 太平廣記 (Extensive Gleanings from the Era of Great Harmony), 10 vols (Beijing: Zhonghua shuju, 1961), ix, 447.3652:

說狐

狐五十歲。能變化為婦人。百歲為美女。為神巫。或為丈夫與女人交接。能知千里外事。善蠱魅。使人迷惑失智。千歲即與天通。為天狐。

出玄中記